N-key rollover

This is a feature that certain keyboards have that let the keyboards register each key regardless of other keys being pressed. It is required for Plover. Read the Wikipedia.org(external link) article about Rollover.

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How do I know if my keyboard has N-Key Rollover (NKRO)?

A simple test is to open up a text editor and--while holding down both shift keys--type each letter on your keyboard. If all keys are typed into the text editor, your keyboard probably has nkro.

This site provides a web application that lets you test your keyboard's capabilities for registering multiple key presses. To test, click where it says "click to use", then each key you press lights up green in the picture of a keyboard. Press the middle row keys asdfjkl; and with a normal keyboard only 6 of the 8 keys will light up green, maybe fewer, but if your keyboard has n-key rollover, all 8 will light up green. Then press other multiple-key combinations such as yuhj and see if they all light up green.

Known supported keyboards

The Sidewinder X4 and Filco Majestouch are confirmed to have at least 16-key rollover over USB. Some of the other keyboards are known not to have usable rollover over USB, though they will probably have sufficient rollover over PS2.

Confirmed working steno machines

Plover supports several protocols that are in use by various machines. This means that, in theory, many machines work with Plover. But these machines have been confirmed by users to work with Plover after actually trying it.